One or more embodiments of the inventive subject matter relate to surgical planning for implant of a cardiac medical lead near a heart.
Heart failure is one of the most widespread and devastating cardiac afflictions, currently affecting approximately 6-10% of adults over the age of 65. One factor that contributes to heart failure is asynchronous activation of the ventricles such that the mechanical contraction is not coordinated effectively, thus compromising cardiac function. As a result, the pumping ability of the heart is diminished, and the patient experiences shortness of breath, fatigue, swelling, and other debilitating symptoms. The weakened heart is also susceptible to potentially lethal ventricular tachyarrhythmias.
One promising technique for reducing the risk of heart failure is cardiac resynchronization therapy (CRT), which seeks to normalize asynchronous cardiac electrical activation and the resultant asynchronous contractions. CRT delivers synchronized pacing stimulus to both ventricles using a pacemaker or an implantable cardioverter defibrillator (ICD) equipped with biventricular pacing capability. The synchronized pacing may be in the form of pacing pulses delivered from one or more electrodes on a cardiac medical lead to selected chambers of the heart. The stimulus is synchronized so as to help to improve overall cardiac function. CRT may have the additional beneficial effect of reducing the susceptibility to life-threatening tachyarrhthmias.
Cardiac resynchronization therapy (CRT) is achieved by positioning leads in traditional locations in the right chamber of the heart, and by maneuvering a left ventricular (LV) pacing lead through the coronary sinus and into the veins surrounding the left ventricle. Delivery of this LV lead is a challenging procedure that requires extensive fluoroscopy time for the patient and clinician. Venous anatomy in patients is highly variable. Some patients lack suitable veins for permanent placement of the lead or require the lead to be maneuvered through sharp angles.
Physicians may not readily recognize how challenging a particular patient's venous anatomy is until the procedure to implant a cardiac medical lead is underway. The physician will select an implant site and begin with his or her preferred implant tools and medical lead. The physician then escalates to more complex tools and/or different leads in the event an attempt fails to locate the lead at a desired implant site. The procedure, extended by the failed attempts, increases radiation exposure due to the extended fluoroscopy time, risks damage to the patient's veins, increases use of nephrotoxic contrast agents used in the fluoroscopy, leads to patient anxiety, and frustrates medical personnel. Eventually, the physician may ask for another physician to step in and take over, or may settle for a suboptimal, but easier to reach, location for the lead.
Accordingly, it would be beneficial to obtain pre-surgical and/or intraoperative knowledge of a patient's venous anatomy in and around the heart and to use that knowledge to provide guidance for physicians before and/or during the lead implantation procedure. Such surgical guidance may reduce or obviate the problems identified above that are associated with traditional lead implantation procedures.